Actions to mitigate sediment buildup could include dredging, streambank stabilization

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Sedimentation by the numbers

Here’s how Lawrence area lakes compare to John Redmond in capacity loss, based on the most recent surveys for each body of water.

Clinton Lake

Original capacity (1977): 129,171 acre-feet

2009 capacity: 118,699 acre-feet

Estimated current capacity: 118,026 acre-feet

Loss of capacity to date: 8.6 percent

Perry Lake

Original capacity (1960): 243,220 acre-feet

2009 capacity: 200,004 acre-feet

Estimated current capacity: 197,843 acre-feet

Loss of capacity to date: 18.7 percent

John Redmond Lake

Original capacity (1963): 82,230 acre-feet

2007 capacity: 50,040 acre-feet

Estimated current capacity: 47,068 acre-feet

Loss of capacity to date: 42.8 percent

Source: Kansas Water Office, kwo.org

Contributed image

A slide from a presentation at the Kansas Water Authority's July Reservoir Advisory Committee meeting compares Kansas reservoirs' loss of capacity to date.

Contributed image

A slide from a presentation at the Kansas Water Authority's July Reservoir Advisory Committee meeting shows visits per year and economic benefit of the state's reservoirs.

Two-thirds of Kansans rely on water from the state’s federal reservoirs, for everything from drinking and bathing to irrigation and power, the Kansas Water Office estimates.

And as decades worth of sediment flows into them, those reservoirs are shrinking — some drastically.

Reservoir sustainability, including dredging and streambank stabilization efforts, is expected to be a key focus of a new long-term water policy plan ordered by Gov. Sam Brownback.

Lawrence City Manager David Corliss, a Kansas Water Authority member who also serves on the state’s Reservoir Advisory Committee, said there’s a sense of urgency when it comes to conserving the Ogallala Aquifer of western Kansas — another priority for Brownback’s plan. Corliss said reservoirs don’t seem to incite the same urgency, yet solutions are needed for their long-term issues.

“What we hope is that a plan can be developed, and more importantly a plan can be funded, so that Kansas communities that depend on reservoirs for their water supply will have the assurance that that water supply will be available for decades to come,” Corliss said.

‘50-year vision’

Two weeks ago, Brownback announced his directive for five state agencies and a council of economic advisers to begin work on what he’s calling a “50-year vision” for water policy in Kansas.

The governor’s announcement came at the beginning of a two-day conference in Manhattan on water issues. He said the persistent drought in the western half of the state shows the importance of water to the Kansas economy.

Droughts are nothing new to the Midwest, and they’re not going away. But Susan Metzger, chief of planning and policy for the Water Office, said episodes like the drought of recent years push water sustainability into the limelight.

“I think it puts some pressure on the long-term vision,” she said. “It certainly makes the public more aware of the value of our water resources.”

Dredging and prevention

Metzger said the governor wants the plan to be broken down into 20-year goals and manageable 5-year actions.

The project marks the first time a non-federal sponsor has pursued dredging a federal facility, Metzger said. She said the process could be applied to other Kansas lakes in the future.

Could that include dredging at Clinton and Perry lakes?

Possibly, Corliss said.

Ideally, though, any long-term plan would call for less expensive preventative measures to be applied first, he said.

And for now, Clinton and Perry don’t face anywhere near the same capacity loss as John Redmond. Clinton has lost 8.6 percent of its capacity since 1977 and Perry has lost 18.7 percent since 1960, according to Water Office estimates.

At Clinton and Perry lakes, streambank restoration and similar efforts to reduce inflow of sediment are already taking place.

Corliss said it’s too soon to tell whether those measures alone will be enough to prevent the need for dredging in the long-term.

“It is very expensive,” Corliss said. “And I think that’s why you want to look at doing things upstream before you do things downstream.”